1. Field of the Invention
The present invention relates to a braking assembly, and in particular, but not exclusively, to a braking assembly for use with a vehicle such as a supermarket shopping trolley or cart.
2. The Prior Art
Various systems have been proposed for impeding or deterring removal of supermarket shopping trolleys or carts from the vicinity of a supermarket. For instance, it has been suggested that physical obstacles such as grids and/or narrow stalls should be placed at the exit points of the supermarket or the supermarket parking lot. The obstacles are intended to interact with the trolley""s castor wheels or with the trolley itself to impede its removal. These known systems are easily overcome and are unsuitable for use in certain locations, such as motor vehicle entrances for supermarket parking lots.
A braking device designated to overcome these problems is described in International Patent Application Nos. WO 92/15476 and GB 97/00847. The braking device is actuated as it passes over a member or an area of magnetic material to cause a braking member to be applied to the ground to impede the continued movement of the shopping trolley. The braking device is conveniently associated with a castor wheel of the trolley. Other types of braking device utilising a braking member to impede the movement of a trolley are known and these devices and the device described in WO 92/15476 and GB 97/00847 are generally effective in impeding or deterring removal of a trolley from a designated area.
The present invention provides an improved vehicle braking assembly for a wheel of a vehicle, the assembly including a main body, a braking member arranged to move relative to the main body between an inoperative and an operative braking position, blocking means for normally blocking movement of the braking member to its operative position, and trigger means, which act in response to the main body being passed over magnetic material to release the blocking means to allow movement of the braking member to its operative position in which it is arranged to contact a surface over which the assembly is passed to impede movement of the wheel relative to the surface, by acting to cause the wheel to be raised relative to the surface, wherein in its operative position the braking member is disposed between the wheel and the surface.
The advantages of this novel arrangement are: the braking member comes between the surface and the wheel forming a more effective braking action; as the braking force is now central rather than to one side, as in known devices, there is no turning of the castor and associated loss of braking effect; known braking devices may skate, rather than grip, on smooth surfaces typically used in retail establishmentsxe2x80x94this is no longer true as the leading edge of the second member is preferably narrow and easily trapped and drawn between the wheel and the floor; and known devices may be vulnerable to vandalism if the main body is rotated, e.g. by being kicked, to prevent the braking member from coming into contact with the groundxe2x80x94if the main body of the present invention is interfered with in such a manner, the braking member will operate straight away and no further interference or vandalism will assist in overcoming the braking effect.
The braking member is preferably mounted co-axially with the wheel. Preferably the braking member is tapered inwardly in the direction of rotation from the inoperative position to the operative position. The braking member may comprise a first portion overlying a portion of the wheel and having an outermost surface for frictional engagement with the surface, and a second portion mounted on the first portion and disposed between the first portion and the main body. The second portion of the braking member may comprise a plate or disc-like member mounted co-axially with the wheel. The braking member may have an elongate channel or slot to permit relative movement of the braking member relative to the wheel to move the braking member closer to the wheel in the operative position.
Cooperating formations project laterally of the trigger means and the braking member to engage when the braking member is in its inoperative position to prevent movement of the braking member to its operative position.
The assembly is preferably fitted to the fork of a castor with the braking member and the vehicle wheel housed within the castor fork. The location of the braking member within the fork further improves the resistance of the device to vandalism.
The present invention also provides a trolley, cart or another vehicle with a braking device of the type discussed above fitted to the fork of a castor.
Further, the present invention provides a braking system comprising the trolley, cart or another vehicle referred to in the previous paragraph, and a strip of magnetic material for mounting in conjunction with the ground, the magnetic material being arranged to cause release of the blocking means upon the passage of the castor over the magnetic material.
A clear understanding of the present invention will be gained from the following detailed description of a preferred embodiment of the invention given by way of example only, with reference to the accompanying drawings.